Method for treating waste high-polymer mixture

Abstract

A method for treating a waste high-polymer mixture by fractionating the mixture consisting essentially of five groups of high polymers, i.e., polyolefinic, polystyrenic, polyvinyl-chloride, thermosetting, and natural high polymers, taking advantage of their dissimilar solubilities in different organic solvents, characterized in that the mixture is brought into contact with o-xylene, p-xylene, or m-xylene, the solvents being used either singly or in a combination of two or more, at temperatures within a certain range or ranges to dissolve and fractionate the polystyrenic and polyolefinic high polymers, and the polyvinyl chlorides in the remainder are dissolved and fractionated by using at least one solvent selected from the group consisting of tetrahydrofuran, cyclohexanone, dioxane, and methylethylketone and at a temperature within a certain range, whereby the waste mixture is fractionated into the groups of polyolefinic, polystyrenic, polyvinyl-chloride, thermosetting, and natural high polymers.

What is claimed is: 
     
       1. A method for treating a waste high-polymer mixture by fractionating the mixture consisting essentially of five groups of high polymers, comprising polyolefinic, polystyrenic, polyvinyl-chloride, thermosetting, and natural high polymers, taking advantage of their dissimilar solubilities in different organic solvents, which comprises bringing the mixture into contact with o-xylene, p-xylene, or m-xylene, the isomers being used either singly or in a combination of two or more, at a temperature between 5° and 50° C to dissolve and fractionate the polystyrenic high polymers, and then at a temperature between 90° and 150° C to dissolve and fractionate the polyolefinic high polymers, and finally dissolving and fractionating the polyvinyl chlorides by heating the remainder in at least one solvent selected from the group consisting of tetrahydrofuran, cyclohexanone, dioxane, and methylethylketone, at a temperature between 5° and 60° C, whereby said waste mixture is fractionated into four groups of high polymers, comprising polyolefinic, polystyrenic, polyviny-chloride, and a mixture of thermosetting and natural high polymers. 
     
     
       2. A method for treating a waste high-polymer mixture by fractionating the mixture consisting essentially of five groups of high polymers, comprising polyolefinic, polystyrenic, polyvinyl-chloride, thermosetting, and natural high polymers, taking advantage of their dissimilar solubilities in different organic solvents, which comprises bringing the mixture into contact with o-xylene, p-xylene, or m-xylene, the isomers being used either singly or in a combination of two or more, at a temperature between 90° and 150° C to dissolve and fractionate the polyolefinic and polystyrenic high polymers, if necessary cooling and fractionating the mixture of polyolefinic and polystyrenic high polymers into the two groups by deposition, and then dissolving and fractionating the polyvinyl chlorides from the rest by use of tetrahydrofuran or cyclohexanone at a temperature between 5° and 60° C. 
     
     
       3. A method according to claim 1, wherein each said organic solvent contains water, an alcohol C n  H 2n   +1  OH (wherein n = 1, 2, 3 or 4), inorganic acid, organic acid, inorganic alkaline compound, or organic basic compound, either singly or in a combination of two or more. 
     
     
       4. A method for treating a waste high-polymer mixture which comprises bringing the mixture consisting essentially of five groups of high polymers, comprising polyolefinic, polystyrenic, polyvinyl-chloride, thermosetting, and natural high polymers, into contact with a mixture of an organic solvent and water to separate the same into two groups comprising (A) a mixed group of polyolefinic, polystyrenic, polyvinyl-chloride, and (B) thermosetting and natural high polymers, drying said natural high polymers by removing the residual organic solvent and water therefrom, and then treating the mixed group of high polymers in accordance with the method set forth in claim 1. 
     
     
       5. A method according to claim 2 wherein each said organic solvent containing a waste high-polymer mixture is placed in contact with water or an alcohol C 2  H 2n   +1  OH (wherein n = 1, 2, 3 or 4) to deposit, separate, and recover the high polymers, and the mixture of the organic solvent and water or alcohol is solidified and separated at low temperatures, and then both of the separated solvents are recycled to the system. 
     
     
       6. A method according to claim 2, which comprises bringing a waste high-polymer mixture containing substances insoluble in the organic solvent used into liquid-to-liquid contact with the organic solvent containing an inorganic acid, organic acid, inorganic alkaline compound, or organic basic compound, either singly or in a combination of two or more, at a temperature between 10° and 150° C, thereby causing chemical reactions of said substances, and then separating and removing said substances to purify said high polymers. 
     
     
       7. A method for treating a waste high-polymer mixture which comprises, in combination, the five steps of: bringing the mixture consisting essentially of four groups of high polymers, comprising polyolefinic, polystyrenic, polyvinyl chloride, and thermosetting high polymers, into contact with an organic solvent, thereby dissolving and fractionating said mixture into three groups, comprising polyolefinic, polystyrenic, and mixed polyvinyl chloride-thermosetting high polymers; removing the solvent from the fractions and recycling the recovered solvent for use in fractionating said waste high-polymer mixture; thermally decomposing said mixture of polyvinyl-chloride and thermosetting high polymers at from 250° to 350° C to recover hydrochloric acid and then at from 400° to 500° C to recover a gaseous or liquid fuel; bringing the fractionated polyolefinic high polymers into contact with the hydrochloric acid obtained by said thermal decomposition and removing the substances soluble in the hydrochloric acid, thereby purifying said polyolefinic high polymers; and burning the high polymers freed of hydrochloric acid or said gaseous or liquid fuel to recover heat or generate steam, and then supplying the recovered heat or generated steam as the source of heat to each of said treatment steps.